''There is really no evidence that taking dietary supplements is beneficial to health, and there is increasing evidence that taking high doses is harmful.''

This can't be stressed enough.

What I don't like (and what makes me question this study) is saying that there is no evidence that taking any dietary supplement can benefit health. The 'any' isn't said but very clearly implied. It reminds me of a study I saw on the 'dangers of taking vitamins' piece where if you actually saw the study you see the only problem was people consistently supplementing with iron, but then writing it up like it generalised to every vitamin.

Also you can talk about outcomes like disease, or being alive or dead, but there is also quality of life to be considered. If taking omega-3 improves your quality if life, like for example your joints does it really make sense to stop using and maybe have to resort to using ibuprofen because you might have an increased chance of cancer? Also there's plenty of medical research showing benefits of omega-3 so I'm curious about this.

Men who eat a lot of oily fish or consume omega supplements should watch out, new research reveals that males with high blood concentrations of omega-3 fatty acids are at a higher risk of developing prostate cancer.

The finding comes from a large prospective study published in the Journal of the National Cancer Institute.

A 71 percent increased risk of high-grade prostate cancer and a 43 percent increase for all prostate cancers were associated with high concentrations of EPA, DHA, and DPA.

These results are consistent with a 2011 study carried out by the same research team which found that high concentrations of DHA more than doubled the risk of high-grade prostate cancer.
The researchers were shocked to find that higher blood levels of omega-3 fatty acids, usually promoted as good for the heart, were associated with a higher risk of aggressive prostate cancer.
The consistency of these findings could mean that "these fatty acids are involved in prostate tumorigenesis and recommendations to increase long-chain omega-3 fatty acid intake, in particular through supplementation, should consider its potential risks."

The paper's senior author and member of the Fred Hutch Public Health Sciences Division, Alan Kristal, Dr.P.H, said: "we've shown once again that use of nutritional supplements may be harmful."

Theodore Brasky, Ph.D., a research assistant professor at The Ohio State University Comprehensive Cancer Cente, added:

"What's important is that we have been able to replicate our findings from 2011 and we have confirmed that marine omega-3 fatty acids play a role in prostate cancer occurrence. It's important to note, however, that these results do not address the question of whether omega-3's play a detrimental role in prostate cancer prognosis."

The study compared the blood level concentrations of omega-3 fatty acids in 834 men who had been diagnosed with prostate cancer with samples from 1,393 men from the Selenium and Vitamin E Cancer Prevention Trial (SELECT).

The lowest risk group for developing prostate cancer had a 3.2 percent blood level concentration of omega-3 fatty acids, compared to 5.7 percent in the high risk group.

The results may come as a surprise to some, considering the number of positive health benefits that are associated with omega-3 fatty acids.

It remains uncertain why high concentrations of these fatty acids are associated with a heightened risk of prostate cancer.

Researchers say it is possible that omega-3 fatty acids are harmful because of they convert into compounds that can damage cells and DNA.

In conclusion, the finding suggests that high levels of omega-3 fatty acids can increase a man's risk of developing prostate cancer.
Written by Joseph Nordqvist